Material datasheet · Low-alloy steel
AISI 4130 Cr-Mo Alloy Steel
UNS G41300 · Normalized or annealed; commonly TIG/MIG welded as tubing
The weldable Cr-Mo alloy steel. Aircraft tubing standard.
Chemical composition
Nominal % by weight.
| Element | % by wt |
|---|---|
| Fe | Bal. |
| C | 0.28–0.33 |
| Cr | 0.80–1.10 |
| Mo | 0.15–0.25 |
Applicable specifications
AMS / ASTM / MIL.
- AMS 6345
- AMS 6360 (tube)
- AMS 6373
- MIL-T-6736
Machining guidance
CNC parameters and tooling.
Carbide; standard geometry
The weldable Cr-Mo. Holds up well after weld + stress relief. Lower hardenability than 4140.
Stock & cost
Forms and Q1 2026 pricing.
- Powder coat
- Paint (zinc primer)
- Phosphate
- Black oxide
Typical applications
Where 4130 Chromoly is the right pick.
- Aircraft tubular structure
- Race car frames
- Firearms barrels
- Bicycle frames
- Roll cages
Alternative materials
Substitute or upgrade options.
- 4140 (higher strength, lower weldability)
- 1020 mild steel (cheaper, lower strength)
True Precision Machining · Buellton, CA
Machine your part in 4130 Chromoly.
5-axis CNC · ISO 9001 · AS9100 · ITAR · CMMC-compliant · DFARS-compliant supply chain. AS9102 FAI on aerospace.
Technically reviewed by the True Precision Machining engineering team · Last reviewed June 2026
Standards referenced: AMS 6345, AMS 6360 (tube), AMS 6373, MIL-T-6736
Keep exploring
Related tools & references
Speeds, feeds, tooling, and chip strategy.
SFM, RPM, and feed rate for this material.
Compare alloys by strength, weight, temperature, and cost.
Estimate part weight from 4130 Chromoly stock.
Aerospace specs that call out this alloy.